The drow of House Udrinor fill the storehouses of Zirnakaynin by virtue of their control over the production and trade in edible fungus within the area of the city. As a sideline they also dipose of bodies within the city using them as compost for their crop or sacrifices to Cyth-V'sug, their patron demon. Matron Holtavoma is the current head and a familiar figure about the city and in the holdings of her house.

It was experimentation by the sporecrafters of House Udrinor that led to the creation of the Vegepygmy race and the Stalking Death.